package chapter04.Example17;
class Animal{
    public void shout(){
        System.out.println("动物叫···");
    }
}
class Dog extends Animal{
    public void shout(){
        System.out.println("汪汪·····");
    }
    public void eat(){
        System.out.println("吃骨头····");
    }
}
public class Example17 {
    public static void main(String[] args) {
        Animal a1 = new Dog();
        System.out.println("Animal a1 = new Dog():"+ (a1 instanceof  Animal));
        System.out.println("Animal a1 = new Dog():"+ (a1 instanceof  Dog));
        Animal a2 = new Animal();
        System.out.println("Animal a2 = new Dog():"+ (a2 instanceof  Animal));
        System.out.println("Animal a2 = new Dog():"+ (a1 instanceof  Dog));
    }
}